Pivotal connection for keys of a musical instrument



3 1968 VAN DER LELY 3,413,885

PIVOTAL CONNECTION FOR KEYS OF A MUSICAL INSTRUMENT Filed Feb. 2, 1 96"? 2 Sheets-Sheet 1 INVENTR. PIET VAN DER LELY AGENT 1968 P. VAN DIER LELY 3413885 PIVOTAL CONNECTION FOR KEYS OF A MUSICAL INSTRUMENT Filed Feb. 2. 1967 FIG.4

INVENTR. PIET VAN DER LELY AGENT 2 Sheets-Sheet 2 United States Patent 3,413,885 PIVOTAL CONNECTION FOR KEYS OF A MUSICAL INSTRUMENT Piet van der Lely, Emmasingel, Eindhoven, Netherlands, assignor to North American Philips Company Inc., New York, N.Y., a corporation of Delaware Filed Feb. 2, 1967, Ser. No. 613,593 Claims priority, application Netherlands, Feb. 17, 1966, 6602034 6 Claims. (Cl. 84435) ABSTRACT OF TH DISCLOSURE This disclosure relates to a means for connecting keys to form a keyboard of a musical instrument. A spring mounted hinged connection intenconnects the key to the instrument, and a guide intersecting the key limits lateral movement of the key.

The invention relates to a keyboard for musical instruments such as an organ having keys whch comprise a first part which is forced, by spring pressure, against a second part which is rigidly secured to the instrument to provide a pivotal connection.

In a known construction, the key comprises, at the area of the pivot, a metal plate whch extends in the longitudinal direction of the key. The plate includes a recess whch opens downwardly and pivots about a circular rod extending in the longitudinal direction of the keyboard. The rod is secured in a hollow square frame whch also extends in the longitudinal direction of the keyboard. In pivot joints of ths type, the key will tilt. This drawback increases as wear occurs.

In order to obtain a more stable construction a guide is used at some distance from the pivot to avoid the tilting. As a result of this constructi-on, the structure becomes statically indetermnate while lateral frictional forces may occur in the hinge so that wear of the keys is promoted whch results in a poor performance.

An object of this invention is to provide a stable statically determinate pivotal connection between the key and the musical instrument.

A further object is to provide a connecton whch avoids tilting and lateral movement of the keys after sustained use.

Another object is to provide a simple economical connection for key operated musical instruments.

According to the invention the pivotal connection between the key and the instrument comprises a wedge member in which the line of intersection of the faces forming the wedge extends in the longitudinal direction of the keyboard and an element whch contacts the wedge member. This element has one surfiace whch contacts one wedge face along a line whch extends in the longitudinal direction of the keyboard and a second surface whch contacts the second wedge face at one point, with the point located in a plane normal to and passing through the center of the line of contact of said first wedge surface. As a result, a pivotal connection is obtained which is free from play and is substantially free of wear. Another feature of the invention is that the bisector plane of the wedge faces extends substantially in the longitudinal direction of the keys. This eliminates tilting of the key and the required height for the key construction is reduced.

According to one embodiment of the invention the line contact between the element and the first wedge takes place only at an area at the ends of the line contacting surfaces. This eliminates the possibility of localized wear at the extremties of the element wherein the line contact could change into a point contact centrally of the original line contact surfaces, thereby making the construction unstable.

The key also includes a guide means remote from the pivotal connecton whch permits pivotal movement of the key but prevents movement in the lateral movement of the key, i.e., movement in the longitudinal direction of the keyboard. The guide means makes the construction statically determin ate.

According to another embodiment of the invention, the angle between the wedge-like faces is chosen to be so that the hinge is self-locking =against tilting of the key.

The invention will nowbe described in greater detail with reference to the drawing, in which:

FIGURE 1 is a perspective View of the key with the pivotal connection in accordance with the invention.

FIGURE 2 is a longitudinal cross-sectional view of the key of FIGURE 1.

FIGURE 3 is a perspective view of a second embodiment of the pivotal connection.

FIGURE 4 shows a longitudinal cross-sectional view of the connection of FIGURE 3.

In FIGURES 1 and 2, the channel member 1 includes a pair of intersecting wedge faces 3 and 4, having a line of intersection at 2. The channel member 1 is rigidly mounted to the musical instrument and provides a mount ing for a series of keys, of which the key 5 is typioal. The key 5 is substantially a rectangular solid having an outer end, which is the end manipulated by a player and is shown at the left of FIGURE 1, and the pivotally mounted end 6. Pivotal end 6 has two rounded sections 8 and 9 whch contact wedge face 3 along the line designated as 7. An additional rounded section 10 centrally located between the sections 8 and 9 contacts the wedge face 4. The bisector plane of the angle between wedge faces 3 and 4 extends subsantially parallel to the longitudinal axis of key 5. The rounded sections 8, 9 and 10 whch pivotally engage the wedge faces of channel 1 are segments of a cylinder having an axis designated as 11 in FIGURE 2. The rounded sections provide a pivotal engagement with the wedge faces 3 and 4 of the channel.

The inner end 6 is held in engagement with the channel 1 by means of a spring 12. The spring 12 is attached to the key 5 and to the channel 1. Spring 12 is p0sitioned in tension at an acute angle to the longitudinal axis of the key 5. Contact between the end 6 of the key 5 and the wedge faces 3 and 4 is continuously maintained by the biasing force of the spring 12. Because the major component of the spring force acts in the direction of the longitudinal axis of the key 5, the force maintaining contact is relatively large in relation to the force component normal to the key 5. This small normal force resists de pression of the key and returns the key to its original position after being deprssed.

The key 5 also includes a pin 13 whch moves in the groove 14 of the channel 1. The pin 13 limits lateral movement of the key. second means is also provided to restrict lateral movement of the end of the key 5 oppo site trom pivoting end 6. A lug 17 which is mounted on the musical instrument and provided with a rubber ring 16 around its free end is inserted into a cavity 15 within the key 5. The key 5 can move vertically on the lug, but lateral movement is restricted by the engagement between the ring 16 and the side walls of the cavity.

FIGURES 3 and 4 illustrate a second embodiment of the pivotal connection, whereby a key 25 engages a channel 26. Key member 25 includes a pair of laterally extending wedge faces 23 and 24 located on end portion 21. The wedge faces intersect at the line designated 22 and define an angle having a bisecting plane which is substantially parallel with the longitudinal axis of the key 25.

Channel 26 is a substantially U-shaped member rigidly attached to the musical instrument (not shown). Included 3 on one leg of the channel are a series of rounded sections 28, 29 and 30. These rounded sections 28, 29 and 30 are sections of a cylinder having an axis at 31.

The wedge faces 23 and 24 of the key 25 engage the leg of the channel 26 such that sections 28 and 29 maintain a line of contact 27 with wedge face 23 and section 30 engages wedge face 24 at a point thereby providing a pivotal connection between the key 25 and the channel 26. The principles relative to the pivotal connection are the same as those of FIGURES 1 and 2. That is, a force applied to the end of the key opposite end 21 will cause the key to pivot on the rounded sections 28-30 of the channel 26.

A tension spring 32 is fastened to retention means on the key 25 and engages the upper leg of the channel 26. The spring 32 is positioned at a slight acute angle with the longitudinal axis of the key 25 thereby providing a substantial contacting force between the key 25 and the channel 26 and provding a slight resistng force to depression of the key 25. The positioning of the spring in the manner illustrated to connect the keys to the istrument provides a keyboard having excellent playing characteristics.

The key 25 is further provided with a pin 33 which is capable of moving in groeve 34 in the longitudinal direction of the key. Since the sides of the groove restrict the pin the key cannot be displaced in the lateral direction at the area of the connection. However, lateral displacement of the key at the end remote from the pivot connection is still possible. In order to prevent this displacement, the key 25 includes a guide assembly which includes a cavity 35 and a lug 37 provided with a rubber ring 36. The lug is rgidly secured to the instrument in a position normal to the axis of the key. This construction permits the key to slide in the vertical direction but restricts lateral movement as well as providing a statically determinate structure. By choosing the angle u between the wedge faces 23 and 24 to be small enough the pivot connection becomes self-locking against tilting of the key 25.

The keys shown in the embodiments of FIGURES 1-2 and FIGURES 3-4 are preferably fabricated from either compressed or molded synthetic resins. These compositions permt simple and economical manufacture of the relatively complicated key shapes. A sheet metal stamping or an extrusion is the preferred means for fabricating the channels.

The above cited embodiments are intended as exemplary only, and while we have described our invention with a specific application and embodiment thereof, other modifications will be apparent to those skilled in the art without departing from the spirit and scope of the invention as defined by the appended claims.

What is claimed is:

1. A connection for attaching a key to a musical instrument to provide pivotal movement in a plane normal to the keyboard containing said key comprising: pivot means, wedge means for engaging said pivot means, said wedge means ncluding a first and a second wedge face which intersect along a line normal to the longitudinal axs of said key and parallel to the keyboard, said pivot means engaging said first wedge face along a line parallel to said line of intersection and engaging said second wedge face substantially at a point with said point of contact lying in a plane normal to and passing through the center of the line of contact on said first wedge face; spring means attached to said pivot means and said wedge means for urging both of said means into biased engagement and for resisting the pivotal motion of said key, and means engaging said key for limiting lateral movement of said key.

2. A connection according to claim 1 wherein the pivot means includes a first rounded section for engaging said first wedge face and a second rounded section for engaging said second wedge face.

3. A connection according to claim 1 wherein the pivot means includes a pair of cylindrical sections engaging said first wedge face at the ends of the line of contact and a cylindrical section engaging said second wedge face, said cylindrical sections having a common axis.

4. A connection according to claim 1 wherein said means for limiting lateral movement of the key includes a pin located on the connecting end of the key and a channel member attached to said musical instrument, said channel being pivotally connected to said key by said pivot means and said wedge means, said channel member including a slot, said pin being confined in said slot when said key is in pivotal engagement with said channel whereby the key can move in a longitudinal direction in said slot and is substantially restricted as to lateral movement in said slot.

5. A connection according to claim 4 wherein said means for limiting lateral movement includes guide means remote from said key to channel pivotal connection, said guide means including a lug attached to said musical instrument and a slot in said key, said lug being insertable in said slot whereby the key is movable in the pivotal plane with respect to said lug and lateral movement of the key with respect to said lug is substantially lmited.

6. A connection for attaching a key to a musical instrument to provide pivotal movement in a plane normal to the keyboard containing said key comprsing a key member having pivot means on one end thereof, a channel member attached to said musical instrument, said channel member includng a first and a second wedge face which intersect along a line normal to the longitudinal axis of said key and parallel to the keyboard, said pivot means engaging said first wedge face along a line parallel to said line of intersection and engaging said second wedge face substantially at a point, with said point of contact lying in a plane normal to and passing through the center of the line of contact on said first wedge ace; spring means attached to said key and to said channel for biasingly engaging the pivot means with said wedge means and for resisting pvoting motion of said key, said limiting means including a pin means located on said key adjacent said pivot means and a slot in one leg of said chan nel aligned with the longitudinal axis of said key, said pin confined by said slot when said pivot means engagcs said wedge means thereby permitting longitudinal movement of said key and limiting lateral movement of said key.

References Cited UNITED STATES PATENTS 2/1967 Klann 84433 

